Light emitting devices and components having excellent chemical resistance and related methods

ABSTRACT

Light emitting devices and components having excellent chemical resistance and related methods are disclosed. In one embodiment, a component of a light emitting device can include a silver (Ag) portion, which can be silver on a substrate, and a protective layer disposed over the Ag portion. The protective layer can at least partially include an inorganic material for increasing the chemical resistance of the Ag portion.

CROSS REFERENCE TO RELATED APPLICATION

This application relates and claims priority to U.S. Provisional PatentApplication Ser. No. 61/510,310, filed Jul. 21, 2011, the disclosure ofwhich is hereby incorporated by reference its entirety.

TECHNICAL FIELD

The subject matter herein relates generally to light emitting devices,components and methods. More particularly, the subject matter hereinrelates to light emitting devices, components and methods with improvedresistance to chemicals and/or chemical vapors or gases that canadversely affect the brightness and reliability of such devices.

BACKGROUND

Light emitting diodes (LEDs), can be utilized in light emitting devicesor packages for providing white light (e.g., perceived as being white ornear-white), and are developing as replacements for incandescent,fluorescent, and metal halide high-intensity discharge (HID) lightproducts. Conventional LED devices or packages can incorporatecomponents such as metallic traces or mounting surfaces which can becometarnished, corroded, or otherwise degraded when exposed to variousundesirable chemicals and/or chemical vapors. Such chemicals and/orchemical vapors can enter conventional LED devices, for example, bypermeating an encapsulant filling material disposed over suchcomponents. In one aspect, undesirable chemicals and/or chemical vaporscan contain sulfur, sulfur-containing compounds (e.g., sulfides,sulfites, sulfates, SO_(x)), chlorine and bromine containing complexes,nitric oxide or nitrogen dioxides (e.g., NO_(x)), and oxidizing organicvapor compounds which can permeate the encapsulant and physicallydegrade various components within the LED device via corroding,oxidizing, darkening, and/or tarnishing such components. Suchdegradation can adversely affect brightness, reliability, and/or thermalproperties of conventional LED devices over time, and can furtheradversely affect the performance of the devices during operation.

Despite the availability of various light emitting devices in themarketplace, a need remains for devices and components having improvedchemical resistance and related methods for preventing undesirablechemicals and/or chemical vapors from reaching and subsequentlydegrading components within the devices. Devices, components, andmethods described herein can advantageously improve chemical resistanceto undesirable chemicals and/or chemical vapors within encapsulated LEDdevices, while promoting ease of manufacture and increasing devicereliability and performance in high power and/or high brightnessapplications. Described methods can be used and applied to createchemically resistant surface mount device (SMD) type of LED devices ofany size, thickness, and/or dimension. Devices, components, and methodsdescribed herein can advantageously be used and adapted within any styleof LED device, for example, devices including a single LED chip,multiple chips, and/or multi-arrays of LEDs and/or devices incorporatingdifferent materials for the body or submount such as plastic, ceramic,glass, aluminum nitride (AlN), aluminum oxide (Al₂O₃), printed circuitboard (PCB), metal core printed circuit board (MCPCB), and aluminumpanel based devices. Notably, devices, components, and methods hereincan prevent degradation of optical and/or thermal properties of devicesor packages incorporating silver (Ag) or Ag plated components bypreventing tarnishing of the Ag or Ag-plated components.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present subject matter includingthe best mode thereof to one of ordinary skill in the art is set forthmore particularly in the remainder of the specification, includingreference to the accompanying figures, in which:

FIG. 1 is a top perspective view of a first embodiment of a lightemitting diode (LED) device according to the disclosure herein;

FIG. 2 is a cross-sectional view of the first embodiment of the LEDdevice according to the disclosure herein;

FIG. 3 is a top perspective view of a second embodiment of an LED deviceaccording to the disclosure herein;

FIG. 4 is a cross-sectional view of the second embodiment of the LEDdevice according to the disclosure herein; and

FIGS. 5 through 13 are cross-sectional views of LED devices according tothe disclosure herein.

DETAILED DESCRIPTION

Reference will now be made in detail to possible aspects or embodimentsof the subject matter herein, one or more examples of which are shown inthe figures. Each example is provided to explain the subject matter andnot as a limitation. In fact, features illustrated or described as partof one embodiment can be used in another embodiment to yield still afurther embodiment. It is intended that the subject matter disclosed andenvisioned herein covers such modifications and variations.

As illustrated in the various figures, some sizes of structures orportions are exaggerated relative to other structures or portions forillustrative purposes and, thus, are provided to illustrate the generalstructures of the present subject matter. Furthermore, various aspectsof the present subject matter are described with reference to astructure or a portion being formed on other structures, portions, orboth. As will be appreciated by those of skill in the art, references toa structure being formed “on” or “above” another structure or portioncontemplates that additional structure, portion, or both may intervene.References to a structure or a portion being formed “on” anotherstructure or portion without an intervening structure or portion aredescribed herein as being formed “directly on” the structure or portion.Similarly, it will be understood that when an element is referred to asbeing “connected”, “attached”, or “coupled” to another element, it canbe directly connected, attached, or coupled to the other element, orintervening elements may be present. In contrast, when an element isreferred to as being “directly connected”, “directly attached”, or“directly coupled” to another element, no intervening elements arepresent.

Furthermore, relative terms such as “on”, “above”, “upper”, “top”,“lower”, or “bottom” are used herein to describe one structure's orportion's relationship to another structure or portion as illustrated inthe figures. It will be understood that relative terms such as “on”,“above”, “upper”, “top”, “lower” or “bottom” are intended to encompassdifferent orientations of the device in addition to the orientationdepicted in the figures. For example, if the device in the figures isturned over, structure or portion described as “above” other structuresor portions would now be oriented “below” the other structures orportions. Likewise, if devices in the figures are rotated along an axis,structure or portion described as “above”, other structures or portionswould now be oriented “next to” or “left of” the other structures orportions. Like numbers refer to like elements throughout.

Unless the absence of one or more elements is specifically recited, theterms “comprising,” including,” and “having” as used herein should beinterpreted as open-ended terms that do not preclude the presence of oneor more elements.

Light emitting devices according to embodiments described herein cancomprise group III-V nitride (e.g., gallium nitride (GaN)) based lightemitting diodes (LEDs) or lasers that can be fabricated on a growthsubstrate, for example, a silicon carbide (SiC) substrate, such as thosedevices manufactured and sold by Cree, Inc. of Durham, N.C. Other growthsubstrates are also contemplated herein, for example and not limited tosapphire, silicon (Si) and GaN. In one aspect, SiC substrates/layers canbe 4H polytype silicon carbide substrates/layers. Other Sic candidatepolytypes, such as 3C, 6H, and 15R polytypes, however, can be used.Appropriate SiC substrates are available from Cree, Inc., of Durham,N.C., the assignee of the present subject matter, and the methods forproducing such substrates are set forth in the scientific literature aswell as in a number of commonly assigned U.S. patents, including but notlimited to U.S. Pat. No. Re. 34,861; U.S. Pat. No. 4,946,547; and U.S.Pat. No. 5,200,022, the disclosures of which are incorporated byreference herein in their entireties. Any other suitable growthsubstrates are contemplated herein.

As used herein, the term “Group III nitride” refers to thosesemiconducting compounds formed between nitrogen and one or moreelements in Group III of the periodic table, usually aluminum (Al),gallium (Ga), and indium (In). The term also refers to binary, ternary,and quaternary compounds such as GaN, AlGaN and AlInGaN. The Group IIIelements can combine with nitrogen to form binary (e.g., GaN), ternary(e.g., AlGaN), and quaternary (e.g., AlInGaN) compounds. These compoundsmay have empirical formulas in which one mole of nitrogen is combinedwith a total of one mole of the Group III elements. Accordingly,formulas such as AlxGa1-xN where 1>x>0 are often used to describe thesecompounds. Techniques for epitaxial growth of Group III nitrides havebecome reasonably well developed and reported in the appropriatescientific literature.

Although various embodiments of LEDs disclosed herein comprise a growthsubstrate, it will be understood by those skilled in the art that thecrystalline epitaxial growth substrate on which the epitaxial layerscomprising an LED are grown can be removed, and the freestandingepitaxial layers can be mounted on a substitute carrier substrate orsubstrate which can have different thermal, electrical, structuraland/or optical characteristics than the original substrate. The subjectmatter described herein is not limited to structures having crystallineepitaxial growth substrates and can be used in connection withstructures in which the epitaxial layers have been removed from theiroriginal growth substrates and bonded to substitute carrier substrates.

Group III nitride based LEDs according to some embodiments of thepresent subject matter, for example, can be fabricated on growthsubstrates (e.g., Si, SiC, or sapphire substrates) to provide horizontaldevices (with at least two electrical contacts on a same side of theLED) or vertical devices (with electrical contacts on opposing sides ofthe LED). Moreover, the growth substrate can be maintained on the LEDafter fabrication or removed (e.g., by etching, grinding, polishing,etc.). The growth substrate can be removed, for example, to reduce athickness of the resulting LED and/or to reduce a forward voltagethrough a vertical LED. A horizontal device (with or without the growthsubstrate), for example, can be flip chip bonded (e.g., using solder) toa carrier substrate or printed circuit board (PCB), or wire bonded. Avertical device (with or without the growth substrate) can have a firstterminal solder bonded to a carrier substrate, mounting pad, or PCB anda second terminal wire bonded to the carrier substrate, electricalelement, or PCB. Examples of vertical and horizontal LED chip structuresare discussed by way of example in U.S. Publication No. 2008/0258130 toBergmann et al. and in U.S. Publication No. 2006/0186418 to Edmond etal., the disclosures of which are hereby incorporated by referenceherein in their entireties.

As described further, one or more LEDS can be at least partially coatedwith one or more phosphors. The phosphors can absorb a portion of theLED light and emit a different wavelength of light such that the LEDdevice or package emits a combination of light from each of the LED andthe phosphor. In one embodiment, the LED device or package emits what isperceived as white light resulting from a combination of light emissionfrom the LED chip and the phosphor. One or more LEDs can be coated andfabricated using many different methods, with one suitable method beingdescribed in U.S. patent application Ser. Nos. 11/656,759 and11/899,790, both entitled “Wafer Level Phosphor Coating Method andDevices Fabricated Utilizing Method”, and both of which are incorporatedherein by reference in their entireties. Other suitable methods forcoating one or more LEDs are described in U.S. patent application Ser.No. 12/014,404 entitled “Phosphor Coating Systems and Methods for LightEmitting Structures and Packaged Light Emitting Diodes IncludingPhosphor Coating” and the continuation-in-part application U.S. patentapplication Ser. No. 12/717,048 entitled “Systems and Methods forApplication of Optical Materials to Optical Elements”, the disclosuresof which are hereby incorporated by reference herein in theirentireties. LEDs can also be coated using other methods suchelectrophoretic deposition (EPD), with a suitable EPD method describedin U.S. patent application Ser. No. 11/473,089 entitled “Close LoopElectrophoretic Deposition of Semiconductor Devices”, which is alsoincorporated herein by reference in its entirety. It is understood thatLED devices, systems, and methods according to the present subjectmatter can also have multiple LEDs of different colors, one or more ofwhich can be white emitting.

Referring now to FIGS. 1 to 13, FIGS. 1 and 2 illustrate top andcross-sectional views of one example of a light emitting diode (LED)package or device, generally designated 10. In one aspect, LED device 10can comprise a surface mount device (SMD) comprising a body 12 which canbe molded or otherwise formed about a leadframe. SMD types of LEDdevices can be suitable for general LED illumination applications, suchas indoor and outdoor lighting, automotive lighting, and preferablysuitable for high power and/or high brightness lighting applications.The subject matter disclosed herein can be suitably adapted forapplication within a wide range of SMD type LED device designs, notlimited to dimensional and/or material variations. Notably, devices,components, and methods disclosed herein can maintain the brightness ofdevice 10 even in the presence of harmful chemicals, chemical vapors, orcomplexes by provision of a protective barrier or protective layer P(FIG. 2) adapted to prevent harmful chemicals or complexes fromtarnishing and/or otherwise degrading components within device 10. Inone aspect, body 12 can be disposed about a leadframe comprising athermal element 14 and one or more electrical elements, for example,first and second electrical elements 16 and 18, respectively. That is,thermal element 14 and electrical elements 16 and 18 can be collectivelyreferred to as a “leadframe” and can be singulated from a sheet ofleadframe components (not shown). A corner notch, generally designated Ncan be used for indicating electrical polarity of first and secondelectrical elements 16 and 18. Thermal element 14 and first and secondelectrical elements 16 and 18 can comprise a material that iselectrically and/or thermally conductive such as a metal or metal alloy.In one aspect, thermal element 14 can be electrically and/or thermallyisolated one and/or both of first and second electrical elements 16 and18 by one or more isolating portions 20 of the body. One or more LEDchips or LEDs 22 can be mounted over thermal element 14 using anysuitable die attach technique(s) and/or material(s), for example onlyand not limited to die attach adhesive (e.g., silicone, epoxy, orconductive silver (Ag) epoxy) or a metal-to-metal die attach techniquesuch as flux or no-flux eutectic, non-eutectic, or thermal compressiondie attach.

LEDs 22 can electrically communicate with one and/or both first andsecond electrical elements 16 and 18 via one or more electricalconnectors such as electrically conductive wire bonds 24. Forillustration purposes, LEDs 22 with two electrical contacts on the sameside (e.g., upper surface) are shown as electrically connected to twoelectrical elements (e.g., 16 and 18) via wire bonds 24. However, LEDs22 having one electrical contact on the upper surface that iselectrically connected with a single electrical element is alsocontemplated. Any type or style of LED 22 can be used in device 10, forexample, LED 22 can comprise a horizontally structured chip (e.g.,having at least two electrical contacts on a same side of the LED) or avertically structured chip (e.g., with electrical contacts on opposingsides of the LED) with or without a growth substrate. LED 22 cancomprise one or more substantially straight cut and/or beveled (i.e.,angled) cut sides or surfaces. LED 22 can comprise a direct attach build(e.g., bonded to a carrier substrate) or a build incorporating a grownsubstrate such as sapphire, SiC, or GaN. LEDs 22 having any build,structure, type, style, shape, and/or dimension are contemplated herein.Wire bonds 24 or other electrical attachment connectors and relatedmethods can be adapted to communicate, transmit, or convey an electricalcurrent or signal from electrical elements 16 and 18 to one or more LEDs22 thereby causing illumination of the one or more LEDs 22. Thermalelement 14 and/or first and second electrical elements 16 and 18,respectively, can be coated, plated, deposited, or otherwise layeredwith a reflective material (FIG. 2), such as, for example and withoutlimitation, Ag or a Ag-containing alloy for reflecting light from theone or more LEDs 22.

Body 12 can comprise any suitable material molded or otherwise disposedabout thermal element 14 and/or first and second elements 16 and 18,respectively. In one aspect, body 12 can comprise a ceramic materialsuch as a low temperature co-fired ceramic (LTCC) material, a hightemperature co-fired ceramic (HTCC) material, alumina, aluminum nitride(AlN), aluminum oxide (Al₂O₃), glass, and/or an Al panel material. Inother aspects, body 12 can comprise a molded plastic material such aspolyamide (PA), polyphthalamide (PPA), liquid crystal polymer (LCP) orsilicone. At least one electrostatic discharge (ESD) protection device25 can be disposed within device 10 and can be electrically connected toelectrical elements 16 and 18 reverse biased with respect to LEDs 22.ESD device 25 can protect against damage from ESD within device 10. Inone aspect, different elements can be used as ESD protection devices 25such as various vertical silicon (Si) Zener diodes, different LEDsarranged reverse biased to LEDs 22, surface mount varistors and lateralSi diodes. As illustrated, ESD device 25 can comprise a verticallystructured device having one electrical contact on the bottom andanother electrical contact on the top; however, horizontally structureddevices are also contemplated.

Still referring to FIGS. 1 and 2, body 12 of device 10 can comprise acavity, generally designated 26, for example, a reflector cavityoptionally coated with a reflective material for reflecting light fromthe one or more LEDs 22. As FIG. 2 illustrates, cavity 26 can be filledat least partially or completely with a filling material, such as anencapsulant 28. Encapsulant can optionally comprise one or more phosphormaterials adapted to emit light of a desired wavelength when activatedby light emitted from the one or more LEDs 22. Thus, in one aspect,device 10 can emit light having a desired wavelength or color point thatcan be a combination of light emitted from phosphors disposed inencapsulant 28 and from the light emitted from one or more LEDs 22. Inone aspect, thermal element 14 and first and second electrical elements16 and 18 can comprise an inner portion 30 and an outer portion 32. Inone aspect, inner portion 30 and outer portion 32 can compriseelectrically and/or thermally conductive materials. Outer portion 32 maybe applied such that it entirely surrounds inner portion 30 as shown, orin other aspects outer portion 32 can optionally plate, coat, orcomprise a layer over a single surface or two or more surfaces ofportion 30.

In one aspect, outer portion 32 can comprise a highly reflective Agsubstrate, substrate containing Ag, or layer of material such as Ag formaximizing light output from device 10 and for assisting in heatdissipation by conducting heat away from the one or more LEDs 22. Outerportion 32 can also comprise a substrate of Ag-containing alloy insteadof pure Ag, and such alloy can contain other metals such as titanium(Ti) or nickel (Ni). Inner portion 30 can comprise a metal or metalalloy such as copper (Cu) substrate or Cu-alloy substrate. In oneaspect, an optional layer of material (not shown) can be disposedbetween inner portion 30 and outer portion 32, such as a layer of Ni forproviding a barrier between the Ag and Cu, thereby preventing defectscaused by migratory Cu atoms, such as a defect commonly known as “redplague”. In other aspects, outer portion 32 can be directly attached toand/or directly coat inner portion 30. Outer portion 32 canadvantageously reflect light emitted from the one or more LEDs 22thereby improving optical performance of device 10. Upper surfaces ofthermal element 14 and electrical elements 16 and 18 can be disposedalong a floor 34 of cavity 26 such that respective upper surfaces ofthermal and electrical elements are disposed along the same plane and/ordifferent planes. First and second electrical elements 16 and 18 canextend from one or more lateral sides of body 12 and form one or moreexternal tab portions, generally designated 36 and 38. Tab portions 36and 38 can bend to form one or more lower mounting surfaces such thatdevice 10 can be mounted to an underlying substrate. Tab portions 36 and38 can outwardly bend away from each other or inwardly bend towards eachother thereby adapting either a J-bend or gull-wing orientation as knownin the art. However, any configuration of external tabs 36 and 38 iscontemplated.

Referring to FIG. 2, a filling material can be disposed and filled toany level within cavity 26 and may be partially disposed below and/orabove a top surface 40 of device 10. In one aspect, filling material cancomprise an encapsulant 28 that it is filled to a level flush with topsurface 40 of device as shown. In other aspects, encapsulant 28 can befilled such that it forms a concave or convex surface with respect totop surface 40 of device 10 as indicated by the dotted lines. In oneaspect, encapsulant 28 can be adapted for dispensing within cavity 26.Encapsulant 28 can comprise a selective amount of one or more phosphorsadapted to emit light or combinations of light providing device 10having a desired color point or color temperature. In one aspect,encapsulant 28 can comprise a silicone material, such as a methyl orphenyl silicone encapsulant.

Typically, SMD type devices, such as device 10, do not have secondaryoptics (e.g., a secondary lens) for preventing harmful chemicals orcomplexes from permeating the device and thereby degrading Ag orAg-alloyed outer portions 32 of thermal and/or electrical elements. Insome aspects, encapsulant 28 can provide physical protection againstforeign solids and liquids, but may not provide adequate protectionagainst gaseous chemicals or airborne elements such as sulfur, oxygen,or moisture which can tarnish or otherwise degrade outer portion 32where outer portion comprises Ag (e.g., pure Ag, Ag-alloys or Agplating). In some aspects, Ag-containing components such as outerportion 32 of thermal and electrical elements 14, 16, and 18 can overtime become tarnished, corroded, or otherwise degraded where the device10 has poor chemical resistance. This can decrease the brightness ofdevice 10. In one aspect, undesirable chemicals, vapors, or complexes Ccan permeate encapsulant 28 and potentially interact with outer portion32 of elements, for example, by tarnishing such elements therebyresulting in degradation to optical, physical, electrical, and/orthermal properties such as a loss in brightness output and thenoticeable darkening of surfaces along cavity floor 34. In thisembodiment, undesirable chemical vapors or complexes C can permeate theencapsulant 28 as indicated by the dotted trajectory lines shown in FIG.2 and could potentially adversely affect outer portion 32 if notdeflected from surfaces within the device as shown. Notably, the currentsubject matter optimizes the chemical resistance of device 10 byincorporating a protective layer P serving as a protective barrier orbarrier layer disposed over one or more surfaces of device 10, withindevice 10, and/or over components of device 10 to prevent complexes Cfrom reaching, interacting with, and/or adversely affecting componentssuch as Ag-containing outer portion 32 of thermal and electricalelements 14, 16, and 18.

As FIG. 2 illustrates, and in one aspect, protective layer P can bedirectly disposed over outer portion 32 of elements as shown alongcavity floor 34. Protective layer P can be applied before attaching theone or more LEDs 22 to thermal element 14 such that protective layer Pcan be disposed between LED 22 and outer portion 32 ofthermal/electrical components or elements. Protective layer P can beused either alone or in combination with a phenyl silicone encapsulantfor improving the chemical resistance of LED devices as describedherein. FIGS. 4 to 13 illustrate various other alternative locations ofprotective layer P for providing protection against chemical complexes Cwithin LED devices or packages. In one aspect, undesired chemicals,vapors, or complexes C can comprise chemical vapors containing sulfur,sulfur containing compounds (sulfides, sulfites, sulfates, SO_(x)),chlorine or bromine containing complexes, nitric oxide or nitrogendioxide (NO_(x)), and/or oxidizing organic vapor compounds. Complexes Ccan degrade the Ag components (e.g., outer portion 32 ofthermal/electrical elements) and result in a loss of brightness outputand noticeable darkening of surfaces within the device. The currentsubject matter can optimize the chemical resistance of device 10 andcomponents within device 10 such that harmful vapors, chemicals, orcomplexes C cannot reach Ag-containing components (e.g., outer portion32) as illustrated by the dotted trajectory of complexes C beingrepelled from the surface of protective layer P, thereby minimizing thedamage to reflective Ag components, and further minimizing and/ortotally preventing any loss in brightness from device 10 and/ordarkening of components within device 10.

Protective layer P can be directly and/or indirectly disposed overvulnerable components within devices described herein, such as locateddirectly or indirectly over Ag or Ag-alloy containing components.Protective layer P can be adapted for application to a variety ofsurfaces of components within LED devices which is advantageous. In oneaspect, protective layer P can be directly applied to portions ofsurfaces of Ag or Ag-alloy containing components (e.g., outer portions32 of thermal element 14 and electrical elements 16, 18) alone and/orlayer P can be applied to portions of surfaces of LED chips 22 includingunderfills, on or over wires, wire bonds 24, wire bond balls (e.g., ballformed where wire 24 attaches to LED chip 22), and on surfaces of theLED housing or body all of which, when comprising a portion or layer ofAg over the surface, can comprise Ag-containing components. Protectivelayer P can be applied over portions of a ceramic or plastic body of LEDdevice, for example, isolating portions 20 of body 12 (FIG. 2). Notably,protective layer P can be selectively applied at or parallel to anynumber of processing steps within the manufacturing process (e.g.,before/after die attachment of LED, before/during/after encapsulation,see FIGS. 4 to 13) for providing broad protection against chemicalvapors, such as but not limited to, nitric oxide or nitrogen dioxide(NO_(x)), oxidizing organic vapor compounds, sulfur, sulfur-containingcompounds (e.g., sulfides, sulfates, SO_(x)) and chlorine- orbromine-containing complexes. Notably, when a protective layer P isincorporated, devices described herein can exhibit excellent chemical,including sulfur, resistance and long lasting protection againstchemical complexes C as compared to conventional devices. In one aspect,improved devices, such as device 10, can retain approximately 95% ormore of its initial brightness value (e.g., measured in lumens) whenexposed to a sulfur environment as compared to conventional deviceswhich may only retain approximately 60% of its initial brightness valuewhen exposed to the same sulfur environment. Depending on the level ofsulfur present and severity of the environment, improved devices such asdevice 10 can retain approximately 100% of their initial brightnessvalue.

Various devices, for example, SMD type devices shown and describedherein can comprise a protective barrier or protective layer P.Protective layer P is not limited in application or use, and can be usedin devices comprising ceramic, plastic, PCB, MCPCB, or laminatesubstrates or submounts and can advantageously be applied over multiplesurfaces, including LEDs 22 disposed within the SMDs. Protective layer Pcan at least partially comprise an inorganic material for increasingchemical resistance of the substrate. The inorganic material cancomprise an inorganic coating, an inorganic film with an organic orsilicone matrix material, and/or an inorganic oxide coating having athickness ranging from approximately 1 nm to 100 μm. As used herein“inorganic coating(s)”, “inorganic layer(s)”, “inorganic film(s)” and/or“inorganic oxide coating(s)” can include some organic material orcomponent in the mixture in addition to the inorganic material orcomponent. Such coating(s), layer(s), and/or film(s) as used herein canbe mostly inorganic, primarily SiO_(x) in nature, however, there maygenerally be some organic component remaining. Any sub-range ofprotective layer P thickness between approximately 1 nm and 100 μm isalso contemplated herein, for example, thicknesses ranging betweenapproximately 1 and 10 nm; 10 nm and 50 nm; 50 nm and 200 nm; 200 nm and400 nm; 400 and 600 nm; 600 and 800 nm; 800 nm and 1 μm; 1 μm and 5 μm;5 μm and 10 μm; 10 μm and 50 μm; and 50 μm and 100 μm are contemplated.Protective layer P can also comprise a thickness ranging fromapproximately 1 nm to 100 nm, 100 nm to 500 nm, and 0.5 μm to 20 μm arealso contemplated herein. In one aspect, a thicker protective layer Pcan provide superior barrier protection of Ag components against harmfulchemical complexes C, thereby improving the brightness retention of LEDdevice 10. Protective layer P can be applied via any suitable technique,such as, for example and without limitation, spinning on, dispensing,brushing, painting, dipping, plating, spraying, screen-printing and/orchemical or physical vapor deposition (CVD or PVD) techniques. Of note,however, spinning on, brushing, painting, spraying, etc. may beadvantageous, as such techniques can be easier to apply than CVD or PVDprocessing (e.g., as such techniques do not require a vacuum, requireless equipment, and reduce the cost).

In one aspect, protective layer P can comprise a Si-containing inorganicoxide coating. For example, protective layer P can comprise an inorganicoxide coating selected from the group consisting of, but not limited to,organosilicate glass, organosilicate solution, organosilicatedispersion, organosilicate sol-gel, Si-containing spin-on glass (SOG)materials, spin-on polymer materials, and/or spin-on dielectricmaterials. As noted earlier, and as used herein “inorganic oxidecoating(s)” are mostly inorganic, primarily SiO_(x) in nature, however,there may generally be some organic component remaining hence the“organosilicate” terminology. Precursors of inorganic or inorganic oxidein solution, dispersion, sol-gel, or liquid form can be used to formprotective layer P. SOG materials can comprise glasses selected fromvarious product or glass families, such as the silicate family,phosphosilicate family, siloxane family, methylsiloxane family,silsesquioxane family, and dopant-containing variations of thesefamilies. Spin-on dielectric materials are mostly delivered in solutionform known as flowable oxides. Spin-on materials can be supplied, forexample, by suppliers such as Filmtronics, Inc., headquartered inButler, Pa., Desert Silicon, LLC headquartered in Glendale, Ariz., orHoneywell Electronic Materials having sales offices in North America,Asia, and Europe.

Dopant-containing SOG or spin-on dielectric materials in variousdelivery forms can also be used to form protective layer P. Notably, theapplication of SOG materials to components within LED devices can beoptimized in terms of adopting novel application methods, curingschedules, and/or curing temperatures. In one aspect, SOG materials canbe, but are not limited to application via spin-on techniques. Forexample, novel methods of applying SOG materials can include dispensing,dipping, painting, screen printing, brushing, and spraying suchmaterials such that they achieve the unexpected result of protecting LEDcomponents from undesirable chemical components which can permeate LEDdevices. Notably, protective layer P can, but does not have to have auniform thickness. Also of note, SOG materials typically need to becured at temperatures of greater than approximately 300° C. In someaspects, SOG materials require curing at temperatures greater thanapproximately 425° C. As LED devices can comprise bodies (e.g., body 12)that are formed from molded plastic which can melt at approximately 300°C. or less, SOG materials can be cured via novel curing schedulesincluding curing at temperatures that are less than approximately 300°C. such that the plastic body is not susceptible to softening and/ormelting. In some aspects, protective layer P can comprise SOG materialscured at temperatures of approximately 300° C. or less such asapproximately 250° C. or less, approximately 200° C. or less,approximately 150° C. or less, or approximately 100° C. or less.

Such novel curing schedules and temperatures can unexpectedly producefilms which do not crack or shrink and which can be useful forprotecting the LED device and/or components within the LED deviceagainst undesirable chemical components that can permeate theencapsulant of LED devices. The SOG materials described herein can bechosen for use depending on the type of package body or device used(e.g., ceramic based body, molded plastic body, etc.) and optimized cureschedules/temperatures and/or application method can be consideredbefore adopting a given material for protective layer P. Conventionalwisdom regarding the manufacture of LED packages or devices conflictswith using SOG materials within and/or over surfaces of such devices, asSOG materials can be difficult to apply, susceptible to cracking and/orshrinking, and can require high curing temperatures. Notably, devicesand components herein can unexpectedly incorporate SOG materials whichare optimized with respect to application and/or curing techniques andadapted for use in LED devices described herein to provide excellentchemical resistance against undesired chemicals, chemical vapors, orchemical complexes which can tarnish, corrode, or adversely affectcomponents and brightness of LED devices.

FIGS. 3 and 4 illustrate top perspective and cross-sectional views ofanother embodiment of an LED package or device, generally designated 50.LED device 50 can also be optimized for chemical resistance byincorporating a protective layer P, for example, on an external surfaceof device 50 and/or on internal surfaces of device (FIG. 4). LED device50 can comprise an SMD type device, similar to device 10 in that asecondary optics is not used. Thus, the possibility of degradation ofdevice components exists where undesirable chemical vapors or complexesC permeate the filling material of the device (FIG. 4). LED device 50can comprise a submount 52 over which an emission area, generallydesignated 54, can be disposed. Emission area 54 can comprise one ormore LEDs 22 disposed under a filling material, such as an encapsulant58 (see FIG. 4). In one aspect, emission area 54 can be substantiallycentrally disposed with respect to submount 52 of LED device 50. In thealternative, emission area 54 can be disposed at any location over LEDdevice 50, for example, in a corner or adjacent an edge. Any location iscontemplated, and more than one emission area 54 is also contemplated.For illustration purposes, a single, circular emission area 54 is shown;however, the number, size, shape, and/or location of emission area 54can change subject to the discretion of LED device consumers,manufacturers, and/or designers. Emission area 54 can comprise anysuitable shape such as a substantially circular, square, oval,rectangular, diamond, irregular, regular, or asymmetrical shape. LEDdevice 50 can further comprise a retention material 56 at leastpartially disposed about emission area 54 where retention material 56can be referred to as a dam. Retention material 56 can comprise anymaterial such as a silicone, ceramic, thermoplastic, and/orthermosetting polymer material. In one aspect, retention material 56 isadapted for dispensing about emission area 54, which is advantageous asit is easy to apply and easy to obtain any desired size and/or shape.

Submount 52 can comprise any suitable mounting substrate, for example, aprinted circuit board (PCB), a metal core printed circuit board (MCPCB),an external circuit, a dielectric laminate panel, a ceramic panel, an Alpanel, AlN, Al₂O₃, or any other suitable substrate over which lightingdevices such as LEDs may mount and/or attach. LEDs 22 disposed inemission area 54 can electrically and/or thermally communicate withelectrical elements disposed with submount 52, for example, conductivetraces (FIG. 4). Emission area 54 can comprise a plurality of LED chips,or LEDs 22 disposed within and/or below a filling material 58 such asillustrated in FIG. 4. LEDs 22 can comprise any suitable size and/orshape of chip and can be vertically structured (e.g., electricalcontacts on opposing sides) and/or horizontally structured (e.g.,contacts on the same side or surface). LEDs 22 can comprise any style ofchip for example, straight cut and/or bevel cut chips, a sapphire, SiC,or GaN growth substrate or no substrate. One or more LEDs 22 can form amulti-chip array of LEDs 22 electrically connected to each other and/orelectrically conductive traces in combinations of series and parallelconfigurations. In one aspect, LEDs 22 can be arranged in one or morestrings of LEDs, where each string can comprise more than one LEDelectrically connected in series. Strings of LEDs 22 can be electricallyconnected in parallel to other strings of LEDs 22. Strings of LEDs 22can be arranged in one or more pattern (not shown). LEDs 22 can beelectrically connected to other LEDs in series, parallel, and/orcombinations of series and parallel arrangements depending upon theapplication.

Referring to FIG. 3, LED device 50 can further comprise at least oneopening or hole, generally designated 60, that can be disposed throughor at least partially through submount 52 for facilitating attachment ofLED device 50 to an external substrate, circuit, or surface. Forexample, one or more screws can be inserted through the at least onehole 60 for securing device 50 to another member, structure, orsubstrate. LED device 50 can also comprise one or more electricalattachment surfaces 62. In one aspect, attachment surfaces 62 compriseelectrical contacts such as solder contacts or connectors. Attachmentsurfaces 62 can be any suitable configuration, size, shape and/orlocation and can comprise positive and negative electrode terminals,denoted by the “+” and/or “−” signs on respective sides of device 50,through which an electrical current or signal can pass when connected toan external power source.

One or more external electrically conductive wires (not shown) can bephysically and electrically attached to attachment surfaces 62 viawelding, soldering, clamping, crimpling, inserting, or using any othersuitable gas-tight solder free attachment method known in the art. Thatis, in some aspects, attachment surfaces 62 can comprise devicesconfigured to clamp, crimp, or otherwise attached to external wires (notshown). Electrical current or signal can pass into LED device 50 fromthe external wires electrically connected to device 10 at the attachmentsurfaces 62. Electrical current can flow into the emission area 54 tofacilitate light output from the LED chips disposed therein. Attachmentsurfaces 62 can electrically communicate with LEDs 22 of emission area54 via conductive traces 64 and 66 (FIG. 4). That is, in one aspectattachment surfaces 62 can comprise a same layer of material as firstand second conductive traces 64 and 66 (FIG. 4) and therefore canelectrically communicate to LEDs 22 attached to traces 64 and 66 viaelectrical connectors such as wire bonds 24. Electrical connectors cancomprise wire bonds 24 or other suitable members for electricallyconnecting LEDs 22 to first and second conductive traces 64 and 66 (FIG.4).

As shown in FIG. 4, a filling material 58 can be disposed between innerwalls of retention material 56. Filling material 58 can comprise anencapsulant that can include a predetermined, or selective, amount ofone or more phosphors and/or lumiphors in an amount suitable for anydesired light emission, for example, suitable for white light conversionor any given color temperature or color point. Alternatively, nophosphors may be included in filling material 58. Filling material 58can comprise a silicon encapsulant material, such as a methyl and/orphenyl silicone material. Filling material 58 can interact with lightemitted from the plurality of LEDs 22 such that a perceived white light,or any suitable and/or desirable wavelength of light, can be observed.Any suitable combination of encapsulant and/or phosphors can be used,and combinations of differently colored phosphors and/or LEDs 22 can beused for producing any desired color points(s) of light. Retentionmaterial 56 can be adapted for dispensing, positioning, damming, orplacing, about at least a portion of emission area 54. After placementof retention material 56, filling material 58 can be selectively filledto any suitable level within the space disposed between one or moreinner walls of retention material 56. For example, filling material 58can be filled to a level equal to the height of retention material 56 orto any level above or below retention material 56, for example, asindicated by the broken lines terminating at retention material 56 shownin FIG. 4. The level of filling material 58 can be planar or curved inany suitable manner, such as concave or convex (e.g., see broken linesin FIG. 4).

FIG. 4 illustrates retention material 56 dispensed or otherwise placedover submount 52 after wire bonding the one or more LEDs 22 such thatretention material 56 is disposed over and at least partially covers atleast a portion of the wire bonds 24. For example, wire bonds 24 of theoutermost edge LEDs in a given set or string of LEDs 22 can be disposedwithin retention material 14. For illustration purposes, only four LEDs22 are illustrated and are shown as electrically connected in series viawire bonds 24, however, device can contain many strings of LEDs 22 ofany number, for example, less than four or more than four LEDs 22 can beelectrically connected in series, parallel, and/or combinations ofseries and parallel arrangements. Strings of LEDs 22 can comprise diodesof the same and/or different colors, or wavelength bins, and differentcolors of phosphors can be used in the filling material 58 disposed overLEDS 22 that are the same or different colors in order to achieveemitted light of a desired color temperature or color point. LEDs 22 canattach to conductive pad 70 or intervening layers (e.g., layers 68and/or protective layer P, described below) disposed between LED 22 andconductive pad 70 using any die attach technique or materials as knownin art and mentioned above, for example epoxy or metal-to-metal dieattach techniques and materials.

LEDs 22 can be arranged, disposed, or mounted over an electricallyand/or thermally conductive pad 70. Conductive pad 70 can beelectrically and/or thermally conductive and can comprise any suitableelectrically and/or thermally conducting material. In one aspect,conductive pad 70 comprises a layer of Cu or a Cu substrate. LEDs 22 canbe electrically connected to first and second conductive traces 64 and66. One of first and second conductive traces 64 and 66 can comprise ananode and the other a cathode. Conductive traces 64 and 66 can alsocomprise a layer of electrically conductive Cu or Cu substrate. In oneaspect, conductive pad 70 and traces 64 and 66 can comprise the same Cusubstrate from which traces 64 and 66 have been singulated or separatedfrom pad 70 via etching or other removal method. After etching, anelectrically insulating solder mask 72 can be applied such that it is atleast partially disposed between conductive pad 70 and respectiveconductive traces 64 and 66. Solder mask 72 can comprise a whitematerial for reflecting light from LED device 50. One or more layers ofmaterial can be disposed between LEDs 22 and conductive pad 70.Similarly, one or more layers of material can be disposed overconductive traces 64 and 66. For example and in one aspect, a firstintervening layer or substrate of material 68 can be disposed betweenLEDs 22 and conductive pad 70 and disposed over traces 64 and 66. Firstlayer of material 68 can comprise a layer of reflective Ag or Ag-alloymaterial for maximizing brightness of light emitted from LED device 50.That is, first layer of material 68 can comprise a Ag or Ag-containingsubstrate adapted to increase brightness of device 50. One or moreadditional layers of material (not shown) can be disposed between firstlayer 68 and conductive pad 70 and/or first layer 68 and traces 64 and66, for example, a layer of Ni can be disposed therebetween forproviding a barrier between the Cu of pad and traces 70, 64, and 66 andthe Ag of layer 68.

Notably, a protective layer P can be at least partially disposed overand/or adjacent to Ag components within device 50, for example, overfirst layer 68 of material which can coat conductive pad 70 and traces64 and 68. Protective layer P can provide a barrier over the Ag coatedcomponents thereby preventing such components from being physically orelectrically degraded via tarnishing, oxidizing, corroding, or otherdegrading phenomenon caused when harmful chemical, vaporous, oratmospheric complexes C permeate filling material 58. As describedearlier, complexes C such as sulfur, sulfides, sulfates, chlorinecomplexes, bromine complexes, NO_(R), oxygen, and/or moisture can damageAg coatings or Ag coated components, such as layer 68 which can coat Cucomponents including pad 70 and/or traces 64 and 66. As describedearlier, protective layer P can comprise an inorganic coating orinorganic oxide coating such as a Si-containing inorganic oxide layerwhich can repel or prevent complexes C from reaching vulnerablecomponents within LED device 50 as shown by the broken lines and arrows.As previously described, protective layer P can comprise an inorganiccoating or inorganic oxide coating selected from the group consistingof, but not limited to, organosilicate glass, organosilicate solution,organosilicate dispersion, organosilicate sol-gel, Si-containing spin-onglass (SOG) materials, spin-on polymer materials, and/or spin-ondielectric materials. Protective layer P can comprise SOG materialsoptimized by implementing novel application and/or curing techniques.That is, SOG materials can be, but do not have to be applied by spin-ontechniques. SOG materials can also be applied via novel applicationmethods such as dispensing, dipping, painting, screen printing,brushing, and spraying such materials which achieve the unexpectedresult of protecting LED components within device 50 from undesirablechemical components or complexes C capable of permeating LED device 50without cracking and/or shrinking, and while maintaining good adhesionwithin device 50. Also of note, SOG materials can be cured via novelcuring schedules including curing at temperatures that are less thanapproximately 300° C. such that LED device 50 and/or components withinLED device 50 (e.g., retention material 56 or encapsulant) are notdamaged by the curing temperature.

FIG. 4 further illustrates a cross-section of submount 52 over whichLEDs 22 can be mounted or otherwise arranged. Submount 52 can comprise,for example, conductive pad 70, first and second conductive traces 64and 66, and solder mask 72 at least partially disposed betweenconductive pad 70 and each of conductive traces 64 and/or 66. Conductivetraces 64, 66 and conductive pad 70 can be coated with a first layer 68,for example Ag. Protective layer P can be disposed over Ag as shown, orsimilar to any of the embodiments illustrated in FIGS. 5 to 13. Submount52 can further comprise a dielectric layer 74, and a core layer 76.Solder mask 72 can directly adhere to portions of dielectric layer 74.For illustration purposes, submount 52 can comprise a MCPCB, forexample, those available and manufactured by The Bergquist Company ofChanhassan, Minn. Any suitable submount 52 can be used, however. Corelayer 76 can comprise a conductive metal layer, for example copper oraluminum. Dielectric layer 74 can comprise an electrically insulatingbut thermally conductive material to assist with heat dissipationthrough submount 52.

As noted earlier, device 50 can comprise a package which does notrequire or use any secondary optics to keep harmful elements fromdegrading conductive pad 70. Notably, devices, components and methodsdisclosed herein provide for improved or optimized chemical resistanceand improved chemical properties where zero or minimum loss ofbrightness occurs, even in the presence of harmful chemicals and can beapplicable to any SMD type device or multi-array device disclosedherein. Such improvements can prevent Ag coated components fromtarnishing, darkening, corroding, or otherwise degrading.

As described earlier, protective layer P can least partially comprise aninorganic material for increasing chemical resistance of the substrate.Such inorganic material of protective layer P can comprise an inorganiccoating, an inorganic film with an organic matrix material, and/or aninorganic oxide coating having a thickness ranging from approximately 1nm to 100 μm. Any sub-range of protective layer P thickness betweenapproximately 1 nm and 100 μm is also contemplated herein, for example,thicknesses ranging between approximately 10 nm and 50 nm; 50 nm and 200nm; 200 nm and 400 nm; 400 and 600 nm; 600 and 800 nm; 800 nm and 1 μm;1 μm and 5 μm; 5 μm and 10 μm; 10 μm and 50 μm; and 50 μm and 100 μm arecontemplated. Protective layer P can also comprise a thickness rangingfrom approximately 1 nm to 100 nm, 100 nm to 500 nm, and 0.5 μm to 20 μmare also contemplated herein.

Of note, one or more additional processing techniques or steps canoptionally be performed during manufacture of devices described hereinfor improving adhesion between one or more layers within the devices.Such optionally processing steps can be used and applied to devicespreviously shown and described, as well as those in FIGS. 5 through 13described hereinbelow. For example, such optional techniques can beperformed to one or more surfaces prior to deposition or application ofone or more adjacent surfaces within a device. Techniques and/oroptional processing steps can be performed on surfaces or layers, suchas, for example and without limitation, Cu surfaces (e.g., inner portion30 of elements 14, 16, and/or 18 of device 10 and/or surfaces ofconductive pad 70, traces 64 and 66 of device 50), Ag surfaces (e.g.,outer portion 32 of elements 14, 16, and/or 18 of device 10, layer ofmaterial 68 of device 50), and/or surfaces of protective layer P. In oneaspect, one or more of these surfaces can be physically, chemically, orthermally prepared or treated to improve adhesion between the treatedsurface and adjacent surface(s) or adjacent layer(s). Optionalprocessing steps that are physical in nature can comprise, for exampleand without limitation, sandblasting, plasma etching, brushing, lapping,sanding, burnishing, grinding, and/or any suitable form of surfaceroughening (e.g., physically texturizing the surface) to improveadhesion between one or more layers or surfaces within devices shown anddescribed herein. Optional processing steps that are chemical in naturecan comprise, for example and without limitation, chemical etching,applying solvents, applying organic solvents, applying acids, applyingbases, vapor degreasing, priming, or any suitable chemically process fortreating a surface to improve adhesion between one or more layers orsurfaces within devices shown and described herein. Optional thermalprocessing steps can comprise, without limitation, prebaking,preheating, or any suitable thermal treatment that improves adhesionbetween one or more layers or surfaces within devices shown anddescribed herein.

FIGS. 5 to 13 are cross-sections of previously described LED device 10which illustrate various locations or placement of protective layer Pwithin and/or over different surfaces of device 10. The location ofprotective layer P shown and described in FIGS. 5 to 13 are equallyapplicable to device 50 (FIGS. 3 and 4) as well as any other LEDcomponent or embodiment (e.g., downset see FIG. 13, through-hole, TVbacklighting downset component), however, for illustration purposes onlydevice 10 has been illustrated in such numerous embodiments. At leastone protective layer P can be used within the LED device for improvingchemical resistance of the device by providing a barrier of protectionagainst chemical complexes C (FIGS. 2, 4). In one aspect, protectivelayer P can prevent Ag components from tarnishing, corroding, darkeningand/or degrading thereby retaining brightness and optical properties ofLED device even in the presence of complexes C (FIGS. 2, 4). FIGS. 5 to13 illustrate a protective coating or layer P which can be applieddirectly and/or indirectly over the Ag coated thermal and electricalcomponents 14 and 16, 18 at different locations with respect to devicecomponents and/or at different stages of production of device 10. Theplacement of protective layer P can be dictated by the order ofprocessing steps. For example, if the LED chip 22 or wire bonds 24 areinstalled before protective layer P is applied, protective layer P willusually coat the LED chips 22 and wire bonds as well as the Ag surface.Other processing steps may involve the masking or removal of protectivelayer P. All processing sequences and therefore placements of protectivelayer P are contemplated and are not limited to such exemplary sequencesand/or locations as described herein.

Two or more protective layers, for example, a first and a secondprotective layer, P1 and P2, respectively, can be used within device 10for protecting against harmful chemical complexes which may permeatedevice 10 and degrade components of device 10 (See FIG. 8). Initially ofnote, and for illustration purposes only, the number of protectivelayers shown herein may be limited to two, however, any suitable numberof protective layers can be applied at any step in the productionprocess and/or at any location within device 10, and such applicationsteps and/or locations are contemplated herein. As described earlier,protective layer P (and/or P1 and P2, FIG. 8) can at least partiallycomprise inorganic material such as an inorganic coating, an inorganicfilm with an organic matrix material, and/or an inorganic oxide coatinghaving a thickness ranging from approximately 1 nm to 100 μm. Anysub-range of thickness between approximately 1 nm and 100 μm iscontemplated. Protective layer P can be delivered and/or applied in anyform to device 10, such as but not limited to application of a solution,dispersion, sol-gel, SOC material (e.g., in solution form), spin-onpolymer material, spin-on dielectric material (e.g., as a flowableoxide) or combinations thereof. Protection layer P can provideprotection against undesired chemicals, chemical vapors, and chemicalcomplexes C (FIGS. 2, 4) serving as an anti-oxidation, anti-corrosionlayer over Ag and Cu, and substrates containing such metals.

As FIG. 5 illustrates, protective layer P can be applied, deposited, orotherwise disposed over electrical and thermal elements 16, 18, and 14before the processing step of molding the device body 12 about theleadframe components. That is, protective layer P can extend to alocation at least partially within a portion of the molded plastic body12 such that it contacts one or more surfaces of body 12. In one aspect,protective layer P can be disposed between one or more portions of body12 as illustrated. Protective layer P can also be disposed between LED22 and outer portion 32 of thermal element 14. As previously described,outer portion 32 can comprise a layer of Ag (or Ag-alloy coating orplating) over which protective layer P can provide a protective barrierfor protecting against complexes which can tarnish, oxidize, or corrodethe Ag. Protective layer P can retain optical properties (e.g.,brightness) of device 10 despite exposure to undesired chemicalcomplexes which may permeate the device. Protective layer P may alsooptionally be applied such that it fully extends over floor 34 of cavity26 and within portions of body 12 such that layer P extends overisolating portions 20 of body as well as Ag coated components (e.g.,over outer portions 32 of elements 14, 16, and 18).

FIG. 6 illustrates an embodiment of device 10 where protective layer Phas been deposited after the processing step of molding the body 12, butprior to the LED die attach step, wire bonding step, and/or applicationof encapsulant 28 step. Thus, protective layer P can extend to alocation within device 10 that is below LED 22 and along at least aportion of cavity floor 34. Protective layer P can extend between uppersurfaces of thermal element 14 and LED 22. In one aspect, protectivelayer P can be disposed over the entire surface of cavity floor 34,thus, disposed over surfaces of each of thermal and electrical elements14, 16, and 18 and isolating portions 20 of body 12. In a furtheraspect, protective layer P can optionally extend along one or more sidewalls of reflector cavity 26 as indicated. In addition, since wirebonding to an inorganic protective layer P may be difficult, additionalprocessing steps such as masking and/or etching protective layer P maybe employed and are contemplated herein.

FIG. 7 illustrates an embodiment of device 10 where protective layer Pcan be applied after the processing step of wire bonding but before theprocessing step of application of encapsulant 28. In one aspect,protective layer P can at least partially coat surfaces of wire bonds24, LED 22, walls of cavity 26, cavity floor 34, and surfaces of thermalelement 14 and electrical elements 16 and 18 (e.g., outer portions 32 ofelements 14, 16, and 18).

FIG. 8 illustrates an embodiment where more than one protective layercan be applied, for example, a first protective layer P1 and a secondprotective layer P2. First and second protective layers P1 and P2 can beapplied at any processing step during production of LED device 10(and/or device 50), thereby assuming the placement illustrated anddescribed in any of FIGS. 2, 4, and 5 to 13 (e.g., the only differencebeing application of more than one protective layer P). Each of firstand second protective layers P1 and P2 can comprise inorganic materialincorporated into an inorganic coating, inorganic oxide coating, orSi-containing coating as previously described. Protective layers P1 andP2 can comprise any thickness ranging from approximately 1 nm to 100 μm.Thicknesses less than 1 nm and/or greater than 100 μm can also be used,however, where more than one layer is present. First and second layersP1 and P2 can be applied as shown over outer portions 32 of thermal andelectrical elements 14, 16, and 18 before die attaching LED 22. Firstand second layers P1 and P2 can optionally extend up side walls ofreflector cavity 26 as shown.

FIG. 9 illustrates another embodiment of device 10, where protectivelayer P has been applied after the processing step of die attach butbefore the step of applying encapsulant 28. That is, protective layer Pcan be located such that it extends about the side and upper surfaces ofLED 22, and over portions of wire bond 24, where wire bond 24 attachesto LED 22 (e.g., at wire bond ball). Protective layer P can also bedisposed entirely over floor 34 of cavity over outer portions 32 ofelements 14, 16, and 18 as well as isolating portions 20 of body 12.Protective layer P can optionally extend up side walls of cavity 26.Notably, protective layer P can, but does not need to comprise a uniformthickness. For example, wetting properties of layer P tend to createthicker areas, or fillets around features within LED device 10. Forexample, layer P may be thicker in areas T surrounding LED 22 asindicated. Thinner areas of protective layer P are also contemplated.

FIG. 10 illustrates an embodiment of device 10 where protective layer Phas been applied after die attachment of LED 22 but prior to applicationof encapsulant 28. As FIG. 10 illustrates, protective layer P can belocated and applied subsequently over a first layer 80. First layer 80can comprise any type of coating or layer, for example, an adhesioncoating or layer, a light-affecting coating or layer, or anotherprotective barrier coating or layer such as an inorganic coating oroxide. In one aspect, first layer 80 comprises a layer oflight-affecting material such as a layer of encapsulant containingphosphor material that emits light of a desired color point whenactivated by light from the LED 22. First layer 80 can be disposedbetween portions of LED 22 and protective layer P, between outerportions 32 of elements 14, 16, and 18 and protective layer P, and/orbetween isolating portions 20 of body 12 and protective layer P. In analternative embodiment, LED chip 22 can comprise a horizontallystructured (i.e., both contacts on the same side, a bottom side) chipthat is directly attached (e.g., no wire bonds) to electrical elements16 and 18. That is, electrical contacts or bond pads (not shown)disposed on a bottom surface of LED 22 could directly attach toelectrical elements 16 and 18 via electrically conductive die attachadhesive (e.g., silicone, epoxy, or conductive silver (Ag) epoxy) suchthat the electrical contacts of LED 22 electrically communicate directlyto elements 16 and 18 without the need for wire bonds 24. First layer 80can then be applied over LED 22 and can comprise a layer of encapsulantcontaining phosphor. Protective layer P can then be applied over each ofLED chip 22 and first layer 80 as indicated.

FIGS. 11 and 12 illustrate further embodiments of device 10, whereprotective layer P has been applied after and/or during the processingstep of application (e.g., dispensing) of encapsulant 28. For example,in FIG. 11, protective layer P can be disposed over an upper surface ofencapsulant 28. Protective layer P can optionally extend over externalsurfaces of device 10, for example, over top surface 40 of body 12.Protective layer P can be disposed at a location such that complexes C(FIG. 2) can be repelled before permeating any portion of encapsulant28. FIG. 12 illustrates protective layer P applied during the processingstep of application of encapsulant 28. In this embodiment, protectivelayer P can be disposed between portions of encapsulant 28, such thatundesirable complexes C (FIG. 2) can be prevented from reaching Agcoated components (e.g., outer portion 32 of elements 14, 16, and 18)thereby preventing any potential damage, corrosion, or darkening thatmay occur to the Ag components. That is, protective layer P can bedisposed between layers or portions of encapsulant 28 or between two ormore separate encapsulation steps. This can advantageously allow device10 to incur approximately zero, or minimal, brightness loss duringoperation, even in the presence of harmful chemicals, chemical vapors,oxygen, or moisture.

FIG. 13 illustrates a further embodiment of device 10. Device 10 cancomprise two electrical elements 16 and 18 to which LED 22 canelectrically connect. Tab portions 36 and 38 can bend inwardly towardseach other thereby adapting either a J-bend. In this embodiment, LED 22can comprise a vertically structured device with a first electricalcontact or bond pad on a bottom surface and a second electrical contactor bond pad on the opposing top surface. The first electrical contactcan electrically and physically connect with first electrical element 16via a die attach adhesive (e.g., silicone, flux, solder, epoxy, etc.)and second electrical contact can electrically and physically connect tosecond electrical element 18 via wire bond 24. In this embodiment, LEDdevice 10 comprises a downset or recessed type of package where LED 22and/or at least a first electrical element can be on a different planethan other components of the LED package or device (e.g., on a differentplane from second electrical element 18). In this embodiment, protectivelayer P can be applied in any of the locations shown in FIGS. 5-12. Forillustrations purposes, protective layer P is shown as applied beforeattaching and wire bonding LED 22. However, any suitable sequence forplacing and/or location of protective layer P is contemplated, forexample, along one or more sidewalls of device 10 and/or applied incombination with other layers. Protective layer P can be applied suchthat it is disposed over a portion of body 12 (e.g., between 16 and 18)and can be subsequently removed as shown via optional masking and/oretching steps if desired.

Embodiments of the present disclosure shown in the drawings anddescribed above are exemplary of numerous embodiments that can be madewithin the scope of the appended claims. It is contemplated that theconfigurations of LED devices optimized for chemical resistance andmethods of making the same can comprise numerous configurations otherthan those specifically disclosed, including combinations of thosespecifically disclosed.

1. A component of a light emitting device, the component comprising: asilver (Ag) portion at least partially disposed over a surface of thecomponent; and a protective layer at least partially disposed over theAg portion, the protective layer at least partially comprising aninorganic material for increasing chemical resistance of the Ag portion,wherein the inorganic material contains some organic component.
 2. Thecomponent of claim 1, wherein the protective layer at least partiallycomprises a silicon containing material selected from the groupconsisting of an organosilicate glass, organosilicate solution,organosilicate dispersion, organosilicate sol-gel, a Si-containingspin-on glass material, a spin-on polymer material, and a spin-ondielectric material.
 3. The component of claim 2, wherein the spin-onglass material comprises a glass family selected from the groupconsisting of a silicate family, a phosphosilicate family, a siloxanefamily, a methylsiloxane family, a silsesquioxane family, and adopant-containing variation of one of these families.
 4. The componentof claim 1, wherein the protective layer comprises a thickness fromapproximately 50 nm to approximately 100 μm.
 5. The component of claim4, wherein the protective layer comprises a thickness from approximately50 nm to approximately 100 nm.
 6. The component of claim 4, wherein theprotective layer comprises a thickness from approximately 100 nm toapproximately 500 nm.
 7. The component of claim 4, wherein theprotective layer comprises a thickness from approximately 0.5 μm toapproximately 20 μm.
 8. The component of claim 1, wherein the Ag portioncomprises a Ag-containing substrate.
 9. The component of claim 8,wherein the protective layer is directly disposed over and on theAg-containing substrate.
 10. The component of claim 8, wherein a lightemitting device is at least partially disposed between the protectivelayer and the Ag-containing substrate.
 11. The component of claim 8,wherein encapsulant is at least partially disposed between theprotective layer and the Ag-containing substrate.
 12. The component ofclaim 8, wherein a layer of phosphor containing material is disposedbetween the protective layer and the Ag-containing substrate.
 13. Thecomponent of claim 8, wherein a layer of material is disposed betweenthe protective layer and the Ag-containing substrate.
 14. The componentof claim 8, wherein the component comprises two or more protectivelayers disposed over the Ag-containing substrate, where each protectivelayer at least partially comprises the inorganic material.
 15. Thecomponent of claim 1, wherein the protective layer is of a non-uniformthickness.
 16. The component of claim 1, wherein the component isincorporated within a surface mount device (SMD) type light emittingdevice.
 17. A light emitting device comprising: a silver (Ag) containingsubstrate; one or more light emitting diodes (LEDs) disposed over theAg-containing substrate; and a protective layer disposed over theAg-containing substrate, the protective layer at least partiallycomprising an inorganic material for increasing chemical resistance ofthe Ag-containing substrate, wherein the inorganic material containssome organic component.
 18. The device of claim 17, wherein theprotective layer at least partially comprises a silicon containingmaterial selected from the group consisting of an organosilicate glass,organosilicate solution, organosilicate dispersion, organosilicatesol-gel, a Si-containing spin-on glass material, a spin-on polymermaterial, and a spin-on dielectric material.
 19. The device of claim 18,wherein the spin-on glass material comprises a glass family selectedfrom the group consisting of a silicate family, a phosphosilicatefamily, a siloxane family, a methylsiloxane family, a silsesquioxanefamily, and a dopant-containing variation of one of these families. 20.The device of claim 17, wherein the protective layer comprises athickness from approximately 50 nm to approximately 100 μm.
 21. Thedevice of claim 20, wherein the protective layer comprises a thicknessfrom approximately 50 nm to approximately 100 nm.
 22. The device ofclaim 20, wherein the protective layer comprises a thickness fromapproximately 100 nm to approximately 500 nm.
 23. The device of claim20, wherein the protective layer comprises a thickness fromapproximately 0.5 μm to approximately 20 μm.
 24. The device of claim 20,wherein the protective layer is directly disposed over the Ag-containingsubstrate.
 25. The device of claim 17, wherein a first LED is at leastpartially disposed between the protective layer and the Ag-containingsubstrate.
 26. The device of claim 17, wherein an encapsulant is atleast partially disposed between the protective layer and theAg-containing substrate.
 27. The device of claim 17, wherein theprotective layer is disposed over an upper surface of an encapsulant.28. The device of claim 17, wherein the protective layer is disposed atleast partially between portions of an encapsulant.
 29. The component ofclaim 17, wherein a layer of material is disposed between the protectivelayer and the Ag-containing substrate.
 30. The device of claim 17,wherein a layer of phosphor containing material is disposed between theprotective layer and the Ag-containing substrate.
 31. The device ofclaim 17, further comprising two or more protective layers disposed overthe Ag-containing substrate, where each protective layer comprises theinorganic material.
 32. The component of claim 17, wherein theprotective layer is of a non-uniform thickness.
 33. The device of claim17, wherein the Ag-containing substrate is contained within a moldedplastic body.
 34. The device of claim 17, wherein the Ag-containingsubstrate is a layer of a submount of the device.
 35. The device ofclaim 17, wherein the Ag-containing substrate is contained within aceramic body.
 36. A light emitting device comprising: a silver (Ag)containing substrate; one or more light emitting diodes (LEDs) disposedover the Ag-containing substrate; a protective layer at least partiallydisposed over the Ag-containing substrate; and a layer of fillingmaterial at least partially disposed over the protective layer; whereinthe protective layer prevents gaseous chemicals or airborne elementsthat have permeated the filling material from interacting with theAg-containing substrate.
 37. The device of claim 36, wherein theprotective layer at least partially comprises an inorganic material, andwherein the inorganic material contains some organic component.
 38. Thedevice of claim 37, wherein the inorganic material comprises a siliconcontaining material selected from the group consisting of anorganosilicate glass, organosilicate solution, organosilicatedispersion, organosilicate sol-gel, a Si-containing spin-on glassmaterial, a spin-on polymer material, and a spin-on dielectric material.39. The device of claim 38, wherein the spin-on glass material comprisesa glass family selected from the group consisting of a silicate family,a phosphosilicate family, a siloxane family, a methylsiloxane family, asilsesquioxane family, and a dopant-containing variation of one of thesefamilies.
 40. The device of claim 36, wherein the Ag-containingsubstrate is at least partially disposed over a copper (Cu) component.41. The device of claim 40, wherein the Ag-containing substrate is atleast partially disposed within a molded plastic body of the device. 42.The device of claim 40, wherein the Ag-containing substrate is at leastpartially disposed within a ceramic body of the device.
 43. The deviceof claim 40, wherein the Ag-containing substrate is at least partiallydisposed over a submount of the device, the submount comprising aprinted circuit board (PCB), a metal core printed circuit board (MCPCB),or an aluminum panel.
 44. The device of claim 36, wherein the fillingmaterial comprises a silicone encapsulant having a selective amount ofphosphor material disposed therein.
 45. The device of claim 44, whereinthe silicone encapsulant comprises a methyl silicone.
 46. The device ofclaim 44, wherein the silicone encapsulant comprises a phenyl silicone.47. The device of claim 44, wherein a retention material is disposedabout the silicone encapsulant.
 48. The device of claim 44, wherein thesilicone encapsulant is disposed within a cavity of the device.
 49. Thedevice of claim 36, wherein the protective layer comprises a thicknessfrom approximately 50 nm to approximately 100 μm.
 50. The device ofclaim 49, wherein the protective layer comprises a thickness fromapproximately 50 nm to approximately 100 nm.
 51. The device of claim 49,wherein the protective layer comprises a thickness from approximately100 nm to approximately 500 nm.
 52. The device of claim 49, wherein theprotective layer comprises a thickness from approximately 0.5 μmapproximately 20 μm.
 53. The device of claim 36, wherein the protectivelayer is directly disposed over the Ag-containing substrate.
 54. Thedevice of claim 36, wherein a portion of a first LED is at leastpartially disposed between the protective layer and the Ag-containingsubstrate.
 55. The device of claim 36, wherein the encapsulant is atleast partially disposed between the protective layer and theAg-containing substrate.
 56. The component device of claim 36, wherein alayer of material is disposed between the protective layer and theAg-containing substrate.
 57. The device of claim 36, wherein a layer ofphosphor containing material is disposed between the protective layerand the Ag-containing substrate.
 58. The device of claim 36, furthercomprising two or more protective layers disposed over the Ag-containingsubstrate, where each protective layer comprises the inorganic material.59. The device of claim 36, wherein the protective layer is of anon-uniform thickness.
 60. A method of providing a component of a lightemitting device, the method comprising: providing a component of a lightemitting device, the component having a silver (Ag) portion thereon; andapplying a protective layer over the Ag portion, the protective layer atleast partially comprising an inorganic material that increases chemicalresistance of the Ag portion, and wherein the inorganic materialcontains some organic component.
 61. The method of claim 60, whereinapplying the protective layer comprises applying a silicon containingmaterial selected from the group consisting of an organosilicate glass,organosilicate solution, organosilicate dispersion, organosilicatesol-gel, a Si-containing spin-on glass material, a spin-on polymermaterial, and a spin-on dielectric material.
 62. The method of claim 61,wherein applying the spin-on glass material comprises applying a glassfamily selected from the group consisting of a silicate family, aphosphosilicate family, a siloxane family, a methylsiloxane family, asilsesquioxane family, and a dopant-containing variation of one of thesefamilies.
 63. The method of claim 60, wherein applying the protectivelayer comprises using a spin-on, brushing, painting, dipping, plating,spraying, screen-printing, a physical vapor deposition (PVD), or achemical vapor deposition (CVD) technique.
 64. The method of claim 60,wherein applying the protective layer comprises applying a layer havinga thickness from approximately 50 nm to approximately 100 μm.
 65. Themethod of claim 64, wherein applying the protective layer comprisesapplying a layer thickness from approximately 50 nm to approximately 100nm.
 66. The method of claim 64, wherein applying the protective layercomprises applying a layer from approximately 100 nm to approximately500 nm.
 67. The method of claim 64, wherein applying the protectivelayer comprises applying a layer from approximately 0.5 μm toapproximately 20 μm.
 68. The method of claim 60, further comprisingcuring the protective layer.
 69. The method of claim 68, wherein curingthe protective layer comprises curing at a temperature of approximately300° C. or less.
 70. The method of claim 68, wherein curing theprotective layer comprises curing at a temperature of approximately 250°C. or less.
 71. The method of claim 68, wherein curing the protectivelayer comprises curing at a temperature of approximately 200° C. orless.
 72. The method of claim 68, wherein curing the protective layercomprises curing at a temperature of approximately 150° C. or less. 73.The method of claim 68, wherein curing the protective layer comprisescuring at a temperature of approximately 100° C. or less.
 74. The methodof claim 60, further comprising preparing a surface of the Ag portion orthe protective layer via sandblasting, plasma etching, brushing,lapping, sanding, burnishing, or grinding.
 75. The method of claim 60,further comprising chemically treating a surface of the Ag portion orthe protective layer via chemical etching, applying solvents, applyingorganic solvents, applying acids, applying bases, vapor degreasing, orpriming.
 76. The method of claim 60, further comprising thermallytreating a surface of the Ag portion or the protective layer viaprebaking or preheating.
 77. The method of claim 60, wherein theprotective layer is applied prior to molding a body of the lightemitting device.
 78. The method of claim 60, wherein the protectivelayer is applied prior to die attaching at least one light emittingdiode (LED) of the light emitting device.
 79. The method of claim 60,wherein the protective layer is applied prior to applying encapsulationto the light emitting device.
 80. The method of claim 60, wherein theprotective layer is applied after applying encapsulation to the lightemitting device.